The state's casinos reported $71.2 million in revenue in May while Ohio's five racinos - which offer horse racing and slot machines, but no table games - made $55.7 million in profit.

But with new racinos slated to open this fall in Dayton and in the Youngstown area, the racinos could soon become the overall revenue leader.

Slot machines at the racinos are already taking in more money than the slots at casinos in Cleveland, Columbus, Toledo and Cincinnati.

Experts are telling the Dayton Daily News that the key is location.

"The advantage the racinos have is that the majority of them are in the suburbs and a lot of people don't want to drive into the main cities," said Alan Silver, an Ohio University professor and gambling expert. "We're seeing these suburban-type racinos pick up a lot of people."

With seven racinos operating more than 8,500 video lottery terminals - or slot machines - and offering harness or thoroughbred racing, they pose a significant challenge to the state's four casinos, which offer slots and table games.

Ohio voters approved casinos in 2009 and the first one opened in Cleveland in May 2012. Racinos were approved by the state legislature in July 2011. Scioto Downs in Columbus opened as the first racino a year later and last month took in more slots revenue ($12.4 million) than the Hollywood Columbus casino ($12 million).

Silver said he expects the racinos to eventually lobby the state for table games.